Patent GB-320516-A (GB)
Title: Improvements in and relating to talking machines
IPC: G11B17/02
Filed: 1928-10-02
Abstract: 320,516. Waterworth, E. N. Oct. 2, 1928. Multiple machines; returning tone-arm to starting point; stopping.-In a magazine gramophone, the initial position of the tone-arm relative to the record on the turntable is determined by mechanism operated by a member carrying feelers projecting upwards outside the turntable and arranged to be depressed by the undersurface of the record. On the completion of the playing of a record, a lever 30 is caused to rock about its pivot, as described in Specification 281,003, causing a wheel 39 to be rotated through one revolution, after which the lever is returned to its original position by a spring 110. The rotation of the wheel 39 effects a single oscillation of a lever 41 about a pivot 42. During the outward movement of the lever 41, a curved plate 43 thereon engages a wheel 44 on a pivoted frame 45, causing the latter to tilt and thereby lift the tone-arm through a rod 47 extending therefrom. The tone-arm is then moved outwards by the engagement with a pin 49 on a plate 50 secured to the arm of a plate 48 pivoted to the lever 41 and normally held against a stop 132 by a spring 115. After the record has been removed and a fresh one placed in position, the plate 48, on the return movement of the lever 41, engages a pin 75 on the plate 50, whereby the tone-arm is returned inwards until a pin 111 on the plate 50 is arrested by one of two stops 112, 113 on a pivoted member 114, the plate 48 then yielding against its spring 115. The stops 112, 113 serve to stop the tone-arm in position for 12" and 10" records, respectively. The member 114 is rocked under the influence of a spring 117 so as to bring the appropriate stop into the path of travel of the pin 111 by the engagement of the undersurface of the record with one of two feelers 118, 119 carried by a plate 120, the feeler 118 being arranged further away from the centre of the turntable and projecting further upwards than the feeler 119. The plate 120 is pivoted at 121 and influenced by a spring 122 so as to keep a nose 120a against a projection 125 upstanding from the member 114. Towards the end of the return movement of the lever 41, the latter bears against the projection 125, thus returning member 114 to its original position. A foot 123 on the plate 120 co-operates with projections 126, 129 at one end of a bell-crank lever 127, the other end of .which has a slot 128 engaging a pin 83 on a lever 84 pivoted to the lever 30. When the plate 120 is rocked by the weight of a record, the foot 123 bears against the projection 126 and rocks the lever 127, and therefore the lever 84, in an anti-clockwise direction. A pin 86 on the lever 84 is thus moved out of a slot 87 in a rocking plate 88 which has a cam surface 89 engaged by a pin 90 on one end of a bellcrank 91, the other end of which carries a brake pad 92 engaging the inside of the turntable. The pin 86 is held in the slot 87 by a spring 94 except when it is positively moved out by the lever 127. If no record is on the turntable, however, the final movement of the lever 30 causes the pin 86, which then lies in the slot 87, to rock the plate 88, whereby the brake is applied by a spring 93. The shape of the slot 128 is such that, when the lever 30 finally moves back to initial position, the lever 127 is rocked anti. clockwise, so that the projection 129 bears on the foot 123 and rocks the plate 120 so as to bring the feelers 118, 119 out of contact with the record until the end of the playing of the record. In a modification, the feeler 119 is omitted, a stop being provided to arrest the plate 120 in the position corresponding to a 10" record, whereby the stop 113 is automatically placed in the path of the pin 111 unless the feeler 118 is depressed. Specification 300,814 also is referred to in the Provisional Specification.